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- All Subjects: Heat Transfer
- Creators: Mechanical and Aerospace Engineering Program
- Resource Type: Text
It was predicted that increasing the surface area roughness would increase the number of electrons present in the reduction oxidation reaction and decrease the activation resistance of the thermogalvanic system. Decreasing the activation resistance, a component of total internal resistance, would therefore increase the power output of the cell by a small magnitude. The results showed that changing the surface area roughness of the Copper electrodes evidently had no effect on the outputs of the cell system. Additionally, the Seebeck coefficient was also unaffected by the presence of increased surface area roughness.
The work presented in the following paper is part of a continuing effort to better understand the performance of thermogalvanic cells and their heat to electrical energy transfer properties.
This work summarizes the development of a dynamic measurement platform in a cryostat to measure sample temperature response to space-like conditions and the creation a MATLAB theoretical model to predict sample temperature responses in the platform itself. An interesting variable-emittance sample called a Fabry-Perot emitter was studied for its thermal homeostasis behavior using the two developments. Using the measurement platform, it was shown that there was no thermal homeostatic behavior demonstrated by the sample at steady state temperatures. Theoretical calculations show other ways to demonstrate the cooling homeostasis behavior through time-varying heat inputs. Factors within the system such as heat loss and thermal mass contributed to an inhibited sample performance in the platform. Future work will have to be conducted, not only to verify the findings of the initial experiments but also to improve the measurement platform and the theoretical model.
This paper explores to mitigate the issue of Formula SAE brakes vaporizing by creating a computational model to determine when the fluid may boil given a velocity profile and brake geometry. The paper explores various parameters and assumptions and how they may lead to error determining when the brake fluid will vaporize. Common assumptions such as a constant convection coefficient are questioned throughout the paper and compared to methods requiring higher computational power. Throughout this model, a significant dependence on the heat partition factor is found on the final steady state temperature of the brake fluid is found, and a sensitivity analysis is performed to determine the effect of its variation.
Thermophotovoltaic energy conversion is seen as a viable option for efficiently converting heat to electricity. There are three key components to a thermophotovoltaic (TPV) system: a heat source, a heat emitter and a photovoltaic (PV) cell. A heat source heats up the emitter which causes the emitter to release thermal radiation. The photons are absorbed by a PV cell when they are acting above the bandgap energy. The PV cell then generates electricity from this thermal radiation. In theory, efficiency of a TPV system can be well above 50%. In order for TPV to reach large-scale adaptation, an efficiency at or above 20% is needed. In this project, a high-temperature heater capable of reaching 1000K was developed. The heater involved a copper block machined to hold two cartridge heaters, as well as two thermocouples. It has an accompanying copper lid that can be screwed tight to the main block, with an emitter in between. There is an aperture to allow radiation through the casing towards the PV cell. Preliminary thermal analysis showed that the heater provides uniform temperature distribution across the emitter, which is necessary for proper radiation. A mounting system was also designed to implement the heater into the overall TPV system. Current work is being done to lower the radiation loss from the heater and mounting system, as well as implementation of all auxiliary components to begin testing. The maximum temperature of the heater, radiation heat flux received by the cell, and overall power output and efficiency of the system will be tested.